The invention relates to differential drive mechanisms. The invention concerns a differential with a housing containing a pinion in the form of a bevel gear which together with a shaft section--constituting one unit with it and projecting from its wide top face--is held by bearings in the housing, whereby the shaft section may be connected and driven by a drive shaft, a crown gear which operates in conjunction with the pinion and is coupled to or constitutes one unit with a rotating satellite housing located in the housing, in which two freely rotating opposing satellites are held by bearings each of which operate in conjunction with two opposing gears which are each connected to a wheel shaft, whereby the pinion constitutes one unit with a second shaft section--projecting from the narrow top face--which is held in the housing by means of roller bearing which has an outer race installed in an opening in the housing and an inner race installed around the second shaft section. A similar differential is generally known.
When the pinion is manufactured, the last operation on the unit, consisting of a cone and two shaft sections projecting from it, involves the cutting of the teeth in the circumferential bevel surface of the pinion. This is done by means of a rotating cutter making it impossible to prevent parts of the second shaft section from being touched and removed by the cutter. Thus this shaft section no longer has a completely smooth cylindrical outer circumferential surface.
In some known differentials the inner race of the roller bearing, by means of which the second shaft section of the pinion is held in the housing, is formed by an annular element slid over the second shaft section. The disadvantage of this design is that the annular element is subject to deformation because it is not fully supported on the inside. This is because some parts were cut out of the cylindrical circumferential surface of the second shaft section during manufacture. In addition, the annular element is not installed in an immovable fashion. Therefore it can execute relatively small movements during the operation of the differential. Both of the aforementioned disadvantages may entail that the inner race becomes deformed at a fairly early stage and becomes loose, or that its inside flange breaks so that the differential will no longer function properly and has to be repaired prematurely.